I understand your discomfort in this but from the other hand if the image crop boundary stays at the edge of your pasted image then you might not notice it there, especially on white background.
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Tigran KhanzadyanMay 30 '11 at 9:44

I believe this is programmed into the Application and there's no way to alter its behavior. @Tigran raised a valid point. Perhaps a shortcut/gesture to make quickly expand it to all the image would be nice, but I couldn't find such thing.
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Martín MarconciniMay 30 '11 at 10:03

1

I think they could make the marching ants prominent enough that you would notice it. Just seems like a poor design
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Victor GraziMay 30 '11 at 15:21

Well, this is always a matter of prospective. On the other hand if you are just interested to crop a little bit from the edges why not do it in Apple Preview, save it and then paste it into the Keynote. In Preview you can adjust the crop window as you wish from the beginning. Just a thought ...
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Tigran KhanzadyanMay 30 '11 at 17:12

Good idea! Would be nice though if apple just made it work in one application. Thanks!
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Victor GraziMay 30 '11 at 20:14